update ci for codecov

Author: refraction-ray

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
         run: |
           pytest --cov=tensorcircuit --cov-report=xml -svv --benchmark-skip
       - name: Upload coverage to Codecov
-        if: matrix.os == 'ubuntu-20.04'
+        if: matrix.os == 'ubuntu-22.04'
         uses: codecov/codecov-action@v2
         with:
           verbose: true